Methods and apparatus for monitoring the rotation of a substrate during cleaning

Abstract

Systems, methods, and apparatus for monitoring rotation of a substrate during cleaning are disclosed. The invention may include a substrate cleaner adapted to support and clean a substrate; an optical source adapted to provide a light beam having a path within the substrate cleaner; and an optical sensor positioned along the path so as to receive the light beam from the optical source and adapted to detect an orientation feature on the substrate when the orientation feature traverses the path. The optical sensor includes an array of light detectors. Numerous additional aspects are disclosed.

1 . A system for monitoring rotation of a substrate during cleaning comprising:
 a substrate cleaner adapted to support and clean a substrate;   an optical source adapted to provide a light beam having a path within the substrate cleaner; and   an optical sensor positioned along the path so as to receive the light beam from the optical source and adapted to detect an orientation feature on the substrate when the orientation feature traverses the path,   wherein the optical sensor includes an array of light detectors.   
   
   
       2 . The system of  claim 1 , wherein the orientation feature is at least one of a notch and a flat. 
   
   
       3 . The system of  claim 1 , wherein the path is normal to a major surface of the substrate. 
   
   
       4 . The system of  claim 1 , wherein the path is angled relative to a major surface of the substrate and the path changes to include a reflected portion based on a position of the orientation feature. 
   
   
       5 . The system of  claim 1 , wherein the path is disposed proximate to an edge of the substrate. 
   
   
       6 . The system of  claim 1 , wherein the substrate cleaner deposits a fluid on the substrate during cleaning and wherein the optical sensor is adapted to detect the orientation feature independent of the fluid being present in the path. 
   
   
       7 . The system of  claim 1 , wherein the array of light detectors includes a plurality of light detectors disposed in a line extending radially from a center of the substrate. 
   
   
       8 . An apparatus for monitoring rotation of a substrate comprising:
 an optical source adapted to provide a light beam having a path partially incident on a substrate; and   an optical sensor positioned along the path so as to receive the light beam from the optical source and adapted to detect an orientation feature on the substrate when the orientation feature traverses the path,   wherein the optical sensor includes an array of light detectors.   
   
   
       9 . The apparatus of  claim 8 , wherein the orientation feature is at least one of a notch and a flat. 
   
   
       10 . The apparatus of  claim 8 , wherein the path is normal to a major surface of the substrate. 
   
   
       11 . The apparatus of  claim 8 , wherein the path is angled relative to a major surface of the substrate and the path changes to include a reflected portion based on a position of the orientation feature. 
   
   
       12 . The apparatus of  claim 8 , wherein the path is disposed proximate to an edge of the substrate. 
   
   
       13 . The apparatus of  claim 8 , wherein the optical sensor is adapted to detect the orientation feature independent of changes in an amount of the light beam being obstructed from reaching the optical sensor. 
   
   
       14 . The apparatus of  claim 8 , wherein the array of light detectors includes a plurality of light detectors disposed in a line extending radially from a center of the substrate. 
   
   
       15 . A method of monitoring rotation of a substrate during cleaning comprising:
 projecting a light beam, having a path, within a substrate cleaner;   traversing the path with an orientation feature of a substrate; and   changing a state of at least one light detector of an optical sensor that includes an array of light detectors, when the orientation feature traverses the path.   
   
   
       16 . The method of  claim 15  wherein projecting a light beam includes projecting a light beam at an edge of a substrate so that the light beam is partially incident on the edge of the substrate. 
   
   
       17 . The method of  claim 15  wherein projecting a light beam includes projecting a light beam at an edge of a substrate so that the light beam is substantially normal relative to a major surface the substrate. 
   
   
       18 . The method of  claim 15  wherein projecting a light beam includes projecting a light beam at an edge of a substrate so that the light beam is angled relative to a major surface the substrate. 
   
   
       19 . The method of  claim 18  wherein projecting a light beam includes projecting a light beam so that the path includes a reflected portion. 
   
   
       20 . The method of  claim 15  wherein traversing the path with an orientation feature of the substrate includes rotating the substrate to cause the orientation feature to pass through the light beam. 
   
   
       21 . The method of  claim 15  wherein changing the state of at least one light detector results from the orientation feature allowing at least some of the light beam to reach the optical sensor when the orientation feature traverses the path. 
   
   
       23 . The method of  claim 15  wherein changing the state of at least one light detector results from the orientation feature preventing at least some of the light beam from reaching the optical sensor when the orientation feature traverses the path. 
   
   
       24 . The method of  claim 15  wherein the array of light detectors is disposed to allow the state of at least one light detector to change in response to the orientation feature traversing the light beam even if the orientation feature is partially blocked. 
   
   
       25 . The method of  claim 15  further including adjusting a speed of rotation of the substrate based on a rate at which the at least one light detector changes state.